Example

For example, if your form should allow support only if linux is selected:

from ddf import shortcuts as ddf

class TestForm(ddf.FormMixin, forms.Form):
    platform = forms.ChoiceField(choices=(
        ('Linux', 'Linux'),
        ('Windows', 'Windows'),
    ))
    service = forms.ChoiceField(choices=(
        ('Format', 'Format'),
        ('Support', 'Support')
    ))

    # Remove the 'Support' choice from the 'service' field if 'platform'
    # value is 'Windows':
    _ddf = dict(
        service=[
            ddf.RemoveChoices(
                ['Support'],
                ddf.ValueIs('platform', 'Windows'),
            )
        ]
    )

In this example, we create a configuration field and add the RemoveChoices action to the service field, with the condition that the platform field value is Windows.

The configuration field is able to render the configuration as a JSON dict, with the form prefix it’s being rendered with. Then, the equivalent of each Action and Condition objects are instanciated in JavaScript, allowing dynamic user experience.

A configuration is structured as such: for each field, you may add a list of actions, for each action a list of conditions. When the user changes a field, each action’s conditions are evaluated and if they all pass then the action is applied, otherwise it is unapplied. Possibilities are huge here.

Dual-license

It is released with the Creative Commons Attribution-NonCommercial 3.0 Unported License, but a commercial license is available, please get in touch my username @ yourlabs.org if you are interrested.

Note that the money goes to YourLabs, a non-profit foundation to promote the role of hackers in the process of making our society more fair and free, while using their skills to develop local economy and give internet back to the people.

Status

The project is pretty young, but the basic building blocks are there. We should be able to add actions and conditions easily.

Why

We’ve been inventing this over and over again for years. The first time I invented this was in 2009 and honnestly my python, django and javascript skills were pretty weak back then. Since then, I’ve seen users asking this, paying me as a consultant for this, making pull requests to have this in a per-app basis. It’s about time we have a generic solution that works for all kinds of fields, and not just the ones of the apps we maintain.